Thiruvarur and Cuddalore
FIRST MID TERM TEST - 2024
Standard X - SCIENCE
Part - I
I. Choose the correct answer. (10 x 1 = 10)
1. The unit of 'g' is \(\text{ms}^{-2}\). It can be also expressed as
2. Power of lens is -4D, then it's focal length is
3. 1 mole of any substance contains __________ molecules.
4. Neon shows zero electron affinity due to
5. Oxygen is produced at what point during photosynthesis?
6. In Leech locomotion is performed by
7. Atrioventricular bundle was discovered by
8. The wall of human heart is made of
9. In Reflex action, the reflex arc is formed by
10. The eye defect "Presbyopia" can be corrected by
Part - II
II. Answer any 5 questions. (Q.No.18 is compulsory) (5 x 2 = 10)
11. Define Inertia. Give its classification.
12. State Snell's Law.
13. Differentiate Convex lens and Concave lens.
14. Give any two examples for hetero diatomic molecules.
15. Why should the light dependent reaction occur before the light independent reaction?
16. State whether the statements are True or False. (Correct the false statement)
i) Anaerobic respiration produces more ATP than Aerobic respiration.
ii) Plant lose water by the process of transpiration.
17. Fill in the blanks.
i) Water enters into the root hair cell through __________.
ii) __________ is the longest cell in our body.
18. Calculate the velocity of a moving body of mass 5 kg whose linear momentum is 2.5 kg ms⁻¹.
Part - III
III. Answer briefly any 4 questions. (Q.No.25 is compulsory) (4 x 4 = 16)
19. List out any five properties of light.
20. A is a silvery white metal. A combines with O₂ to form B at 800°C. a) The alloy of A is used in making the aircraft. Find A and B. b) What is Rust?
21. a) Match the following:
- Amphicribal - Dracaena
- Cambium - Fern
- Amphivasal - Secondary growth
- Xylem - Conduction of water
b) Why is the Sinoatrial node called the pacemaker of heart?
22. i) Draw the structure of neuron and label the parts. (2 marks)
ii) Write the reaction of photosynthesis.
23. Enumerate the functions of blood.
24. Differentiate between Aerobic and Anaerobic respiration.
25. Calculate the number of moles in
i) 27 g of Al
ii) \(1.5 \times 10^{23}\) molecules of NH₄Cl
Part - IV
IV. Answer in detailed. (2 x 7 = 14)
26. Deduce the equation of a force using Newton's second law of motion.
(OR)
i) Give the salient features of modern atomic theory. (5 marks)
ii) Assertion and Reason - (2 marks)
Assertion: An uncleaned copper vessel is covered with greenish layer.
Reason: Copper is not attacked by Alkali.
27. Describe and name three stages of cellular respiration that aerobic organisms use to obtain energy from glucose.
(OR)
i) List out the parasitic adaptations in Leech. (5 marks)
ii) Define 'Reflex arc'. (2 marks)
Thiruvarur and Cuddalore
FIRST MID TERM TEST - 2024 (With Solutions)
Standard X - SCIENCE
Part - I
I. Choose the correct answer. (10 x 1 = 10)
1. The unit of 'g' is \(\text{ms}^{-2}\). It can be also expressed as
Explanation: According to Newton's second law, Force \(F = ma\). Gravitational force is \(F = mg\). Therefore, \(g = F/m\). The unit of Force (F) is Newton (N) and the unit of mass (m) is kilogram (kg). Hence, the unit of g is N/kg or \(\text{N kg}^{-1}\).
2. Power of lens is -4D, then it's focal length is
Explanation: The relation between Power of a lens (P) and its focal length (f) is \(P = 1/f\). Thus, \(f = 1/P = 1/(-4) = -0.25\) m. The negative sign indicates it is a concave lens.
3. 1 mole of any substance contains __________ molecules.
Explanation: According to Avogadro's number, one mole of any substance contains \(6.023 \times 10^{23}\) constituent particles (atoms, molecules, ions, etc.).
4. Neon shows zero electron affinity due to
Explanation: Neon is a noble gas with a completely filled valence electron shell. This stable electron configuration makes it energetically unfavorable to accept an additional electron, resulting in zero electron affinity.
5. Oxygen is produced at what point during photosynthesis?
Explanation: During the light-dependent reactions of photosynthesis, light energy is used to split water molecules (photolysis), releasing oxygen, protons, and electrons.
6. In Leech locomotion is performed by
Explanation: The primary mechanism for leech locomotion (looping or crawling) is the coordinated contraction and relaxation of its circular and longitudinal muscles. Suckers are used for attachment.
7. Atrioventricular bundle was discovered by
Explanation: The atrioventricular bundle, a crucial part of the heart's electrical conduction system, was discovered by the Swiss cardiologist Wilhelm His, Jr. in 1893. It is often called the "Bundle of His".
8. The wall of human heart is made of
Explanation: The wall of the human heart is composed of three layers: the outer epicardium, the middle myocardium (muscle layer), and the inner endocardium.
9. In Reflex action, the reflex arc is formed by
Explanation: The simplest reflex arc pathway involves a stimulus detected by a receptor, a sensory neuron sending a signal to the spinal cord, and a motor neuron sending a signal from the spinal cord to an effector (like a muscle) to produce a response.
10. The eye defect "Presbyopia" can be corrected by
Explanation: Presbyopia is the age-related loss of the eye's ability to focus on nearby objects. Since it often coexists with nearsightedness or farsightedness, bifocal lenses (which have corrections for both near and distant vision) are used.
Part - II
II. Answer any 5 questions. (Q.No.18 is compulsory) (5 x 2 = 10)
11. Define Inertia. Give its classification.
Inertia: The inherent property of a body to resist any change in its state of rest or the state of uniform motion, unless it is influenced upon by an external unbalanced force, is known as inertia.
Classification:
- Inertia of rest
- Inertia of motion
- Inertia of direction
12. State Snell's Law.
Snell's Law: The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant for a given pair of media. This constant is the refractive index of the second medium with respect to the first.
Mathematically: \( \frac{\sin i}{\sin r} = \mu \) (constant)
13. Differentiate Convex lens and Concave lens.
| Convex Lens | Concave Lens |
|---|---|
| Thicker at the center and thinner at the edges. | Thinner at the center and thicker at the edges. |
| It converges a parallel beam of light, so it is called a converging lens. | It diverges a parallel beam of light, so it is called a diverging lens. |
| Can form both real and virtual images. | Forms only virtual images. |
| Used to correct hypermetropia (farsightedness). | Used to correct myopia (nearsightedness). |
14. Give any two examples for hetero diatomic molecules.
Answer: Hetero diatomic molecules are composed of two different atoms. Examples include:
- Hydrogen Chloride (HCl)
- Carbon Monoxide (CO)
15. Why should the light dependent reaction occur before the light independent reaction?
16. State whether the statements are True or False. (Correct the false statement)
i) Anaerobic respiration produces more ATP than Aerobic respiration.
Answer: False.
Corrected statement: Aerobic respiration produces much more ATP (approx. 36-38 ATP) than Anaerobic respiration (2 ATP).
ii) Plant lose water by the process of transpiration.
Answer: True.
17. Fill in the blanks.
i) Water enters into the root hair cell through osmosis.
ii) Neuron (nerve cell) is the longest cell in our body.
18. Calculate the velocity of a moving body of mass 5 kg whose linear momentum is 2.5 kg ms⁻¹.
Solution:
Given:
Mass (m) = 5 kg
Linear momentum (p) = 2.5 kg ms⁻¹
Formula: Momentum (p) = Mass (m) × Velocity (v)
Therefore, Velocity \(v = \frac{p}{m}\)
\(v = \frac{2.5 \, \text{kg ms}^{-1}}{5 \, \text{kg}} = 0.5 \, \text{ms}^{-1}\)
Answer: The velocity of the body is 0.5 ms⁻¹.
Part - III
III. Answer briefly any 4 questions. (Q.No.25 is compulsory) (4 x 4 = 16)
19. List out any five properties of light.
- Rectilinear Propagation: Light travels in a straight line.
- Form of Energy: Light is a form of energy.
- Electromagnetic Wave: Light does not require a medium for propagation; it can travel through a vacuum.
- Speed: Light travels at a very high speed of \(3 \times 10^8 \, \text{ms}^{-1}\) in a vacuum.
- Reflection and Refraction: Light bounces off surfaces (reflection) and bends when it passes from one medium to another (refraction).
20. A is a silvery white metal. A combines with O₂ to form B at 800°C. a) The alloy of A is used in making the aircraft. Find A and B. b) What is Rust?
Solution:
a) The metal whose alloy is used in making aircraft is Aluminium. It is a silvery-white metal.
- A is Aluminium (Al).
- Aluminium combines with oxygen at high temperatures to form Aluminium Oxide. So, B is Aluminium Oxide (Al₂O₃).
Chemical Equation: \( 4\text{Al} + 3\text{O}_2 \xrightarrow{800^\circ C} 2\text{Al}_2\text{O}_3 \)
b) Rust is hydrated iron(III) oxide, with the chemical formula Fe₂O₃·nH₂O. It forms when iron or its alloys are exposed to oxygen and moisture for a long time. It is unrelated to Aluminium.
21. a) Match the following:
- Amphicribal - Fern (Phloem surrounds Xylem)
- Cambium - Secondary growth (Responsible for increase in girth)
- Amphivasal - Dracaena (Xylem surrounds Phloem)
- Xylem - Conduction of water
b) Why is the Sinoatrial node called the pacemaker of heart?
Reason: The Sinoatrial (SA) node is called the heart's natural pacemaker because it has the ability to spontaneously generate electrical impulses at the fastest rate in the heart. These impulses spread through the heart, causing it to contract. Since it sets the pace for the heartbeat, it is called the pacemaker.
22. i) Draw the structure of neuron and label the parts. (2 marks)
ii) Write the reaction of photosynthesis.
\[ 6\text{CO}_2 + 6\text{H}_2\text{O} \xrightarrow{\text{Light/Chlorophyll}} \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \uparrow \]
(Carbon dioxide + Water \(\rightarrow\) Glucose + Oxygen)
23. Enumerate the functions of blood.
- Transport: Carries respiratory gases (O₂, CO₂), digested food, hormones, and waste products.
- Protection: White blood cells fight against invading pathogens. Platelets help in blood clotting to prevent excessive blood loss.
- Regulation: Helps in the regulation of body temperature and maintains the pH of the body fluids.
24. Differentiate between Aerobic and Anaerobic respiration.
| Feature | Aerobic Respiration | Anaerobic Respiration |
|---|---|---|
| Oxygen Requirement | Required | Not required |
| Location | Cytoplasm & Mitochondria | Cytoplasm only |
| End Products | CO₂, Water, ATP | Ethanol/Lactic acid, CO₂, ATP |
| Energy Yield | High (36-38 ATP) | Low (2 ATP) |
25. Calculate the number of moles in
i) 27 g of Al
Solution (i): Molar mass of Aluminium (Al) = 27 g/mol.
Number of moles = \(\frac{\text{Given mass}}{\text{Molar mass}}\) = \(\frac{27 \, \text{g}}{27 \, \text{g/mol}}\) = 1 mole.
ii) \(1.5 \times 10^{23}\) molecules of NH₄Cl
Solution (ii): Avogadro's number = \(6.023 \times 10^{23}\) molecules/mol.
Number of moles = \(\frac{\text{Number of molecules}}{\text{Avogadro's number}}\)
= \(\frac{1.5 \times 10^{23}}{6.023 \times 10^{23}}\) ≈ 0.249 moles
Approximately 0.25 moles.
Part - IV
IV. Answer in detailed. (2 x 7 = 14)
26. Deduce the equation of a force using Newton's second law of motion.
Derivation of F=ma from Newton's Second Law:
Statement: Newton's second law of motion states that the rate of change of momentum of a body is directly proportional to the external force applied and takes place in the direction of the force.
Let an object of mass 'm' be moving with an initial velocity 'u'. Let a force 'F' act on it for a time 't', causing its final velocity to become 'v'.
Initial momentum (\(p_i\)) = mu
Final momentum (\(p_f\)) = mv
Change in momentum (\(\Delta p\)) = \(p_f - p_i = mv - mu = m(v-u)\)
Rate of change of momentum = \(\frac{\text{Change in momentum}}{\text{Time}} = \frac{m(v-u)}{t}\)
According to the law, Force ∝ Rate of change of momentum
F ∝ \(\frac{m(v-u)}{t}\)
We know that acceleration (a) = \(\frac{\text{change in velocity}}{\text{time}} = \frac{v-u}{t}\). Substituting this in the equation:
F ∝ ma
To make this an equation, we introduce a proportionality constant 'k'.
F = kma
In the SI system of units, the value of k is chosen as 1. Therefore,
F = ma
Force = Mass × Acceleration. This is the equation for force.
(OR)
i) Give the salient features of modern atomic theory. (5 marks)
- Atom is divisible: An atom is no longer considered indivisible. It is composed of subatomic particles like protons, neutrons, and electrons.
- Isotopes: Atoms of the same element can have different atomic masses. These are called isotopes (e.g., Chlorine-35 and Chlorine-37).
- Isobars: Atoms of different elements can have the same atomic mass. These are called isobars (e.g., Argon-40 and Calcium-40).
- Artificial Transmutation: Atoms of one element can be transformed into atoms of another element by artificial means.
- Mass-Energy Equivalence: Mass can be converted into energy according to Einstein's equation, \(E = mc^2\). The mass of an atom is converted into energy during nuclear reactions.
ii) Assertion and Reason - (2 marks)
Assertion: An uncleaned copper vessel is covered with greenish layer.
Reason: Copper is not attacked by Alkali.
Correct Option: (b) A and R are correct, but R does not explain A.
Explanation:
- Assertion (A) is correct: Copper reacts with moist air (containing CO₂, O₂, and H₂O) over time to form a green layer of basic copper carbonate, \(\text{CuCO}_3\text{.Cu(OH)}_2\).
- Reason (R) is also correct: Copper is a relatively unreactive metal and does not react with alkalis.
- However, the reason does not explain the assertion. The greenish layer is formed due to corrosion by acidic gases in the air, not because of its non-reactivity with alkalis.
27. Describe and name three stages of cellular respiration that aerobic organisms use to obtain energy from glucose.
Energy from Glucose (Aerobic Respiration):
Aerobic organisms break down glucose to release energy (ATP) in a process called cellular respiration. This occurs in three main stages:
1. Glycolysis:
- Location: Cytoplasm.
- Process: One molecule of glucose (6-carbon) is broken down into two molecules of pyruvic acid (3-carbon). This process does not require oxygen.
- Products: A net gain of 2 ATP and 2 NADH molecules.
2. Krebs Cycle (Citric Acid Cycle):
- Location: Matrix of the mitochondria.
- Process: The pyruvic acid from glycolysis is converted into Acetyl-CoA and enters the Krebs cycle. Here, it is completely oxidized, and carbon is released as CO₂.
- Products (per glucose molecule): 2 ATP, 8 NADH, and 2 FADH₂ molecules are generated.
3. Electron Transport Chain (Oxidative Phosphorylation):
- Location: Inner mitochondrial membrane.
- Process: The high-energy electrons from NADH and FADH₂ (produced in the earlier stages) are passed along a series of protein complexes. The energy released is used to pump protons, creating a gradient that drives the synthesis of a large amount of ATP. Oxygen acts as the final electron acceptor, combining with electrons and protons to form water.
- Products: The majority of ATP (about 32-34 molecules) is produced in this stage.
(OR)
i) List out the parasitic adaptations in Leech. (5 marks)
- Suckers: It has an anterior and a posterior sucker, which are used for strong attachment to the host's body.
- Jaws: The mouth is equipped with three jaws that make a painless, Y-shaped incision in the host's skin.
- Anticoagulant (Hirudin): Its salivary glands secrete hirudin, which prevents the host's blood from clotting, ensuring a continuous supply of blood.
- Muscular Pharynx: The pharynx is muscular and acts as a suction pump to draw blood from the host.
- Large Crop: The crop is a large chamber in the digestive tract that can store a huge amount of blood, allowing the leech to survive for months between meals.
ii) Define 'Reflex arc'. (2 marks)
Reflex Arc:
The pathway taken by the nerve impulse to accomplish a reflex action is called the reflex arc. It typically includes a sensory receptor, a sensory neuron, an integration center (like the spinal cord), a motor neuron, and an effector (like a muscle or gland).